Bottom tubing plug for oil wells



Feb. 1, 1938. w. K. EDWARDS BOTTOM TUBING PLUG FOR OIL WELLS Filed May3, 1957 a a 6% Q 4 6 5 A: w a wwfl W bwg 1 V W I \i companying drawing,in which; 4

Patented Feb. '1, 193a,

UNlTED l STATES rA'rENT OFFICE comma.

This invention relates to means for prevent the oil from flowing throughtubing in high pressure oil wells'while the tubing is being run into thewell. V

Means have heretofore been provided for preventing the flow of oilthrough the tubing while the same is being lowered into the well, suchmeans being ordinarily in the form of a disk 4 which is capable ofbeing-punctured, either by a puncturing tool or through impact from aweight which is dropped down the hibing, to allow the oil to flowthrough the tubing after the latter has been inserted in position. Suchdevices are more or less objectionable because fracture of the disk 15.either by a weight dropped into the tubing, or a tool forcibly movedagainst the disk, is possible,

as portions of the disk are frequently not removed by these methods.Thus parts of the disks which remain act as an obstruction to the flow20 of oil, and for this'reason the frangible disk method of checking theflow of oil in tubing hasnot been a success.

An important feature of the present invention consists in a plug whichis held in a position to 25 obstruct the flow of oil through the tubingby frictional means. The plug my be dislodged either by hydraulicpressure applied from above by a pump, or may be knocked out by droppinga weight on it from above. In either case the plug 30 is removed as anobstructing element, as an entirety, and drops through the tubing to thebottom of the well so as to be out of the may. thus permitting a freeflow. of the oil when such result is desired. lreferi ly. the frictionalmeans for retaining the plugin position is, as herein shown, in the formof an split ring of resilient metal which normally expands into a groovein the walls of the tubing, and holds the plug against dislodgment bythe pressure of the oil from below, and retains the plug in positionuntil it is desired to remove it in either. of the ways above mentionedUnder a preferred form of the invention the plugjs in the form of acurved member so that when the plug is dislodged its shape. is such asto prevent the nos- 7 sibility of dislodgment in that portion of thetubing below where-the-plug is placed, as for example, when a perforatedscrew jointof tubingis provided below the plug to'act as a strainer;''50 or where the extension of the well'tubing below the plug is in theform of a pipe section.

v The foregoing, and other important features of the invention will behereinafter 1mpre particularly described in connection with the ac-'tion, and

Fig. 1 is a view, partly sectional, illustrating the preferred form ofmy bottom tubing plug in position in the oil well tubing; L

Fig. 2 is a similar view illustrating a modiflca- 6 Fig. 3 is asectional view on the line 3-4, mg. 1'.

Sections of the oil well tubing l', 2, and 3 are connected by'couplingcollars l and 5, as'is usual.

Referring to Fig. 1, at, a suitable point, preferably near thetermination of a section of tubing 2, a 10 ground valve seat I isprovided. The tubing plug is composed of an upper disk portion 8 and alower extension i0 which, as herein shown, is partly cylindrical andterminates at its lower end in a convexly curved portion l2, this partof, the plug resembling generally the shape of a bullet, or plumb bob.The part II of the plug is provided at its upper terminal with a recessor groove it within which is located an expansion ring l6 having anormal tendency to expand outwardly beyond the plug. This ring, when theplug is in the position shown in Fig. 1 in the tubing, is restrainedagainst outward expansion by a recess il formed in the inner wall of thetubing section 2 a suitable distance below the ground seat I.

The disk-shaped part 8 of the plug seats upon theupp r surface of thelower section In and is clamped in position thereonby a threaded bolt I8having a head l9, and engaging an internal thread in a central orificeof the plug member ID. By such bolt the'parts of the plug, 8, iii, areclamped together and the upper portion of the recess II in the memberIii is closed by the overlapping portion of the disk, thereby forming a,complete groove for the expansible ring it.

It will be seen from the above construction that the bottom tubing plug,comprising the above described parts, is inserted by forcibly moving itupwardly in the tubing until the upper face of 0 the disk 8 seatsagainst the ground seat I, the expansion ring being forced inwardlyduring such movement and contracted until the plug has become seated,whereupon the ring expands outwardy beyond the perimeter of thecylindrical 4:; portion of the plug member ID, and frictionally holdsthe plug as an entirety snugly and reliably within .the tubing. When inthis position the diskaisseatedonthegroundjointlandanoil tight joint isthus formed to prevent the possiso bility of any oil passing above theplug, due to' y the oil pressure in the well; The'inner surface of thetubing section 2, below the [seat n 101- the expansion ring; is inwardlybeveled as indicated at 2., so that in the operation of! forcing theplug 5 tubing at the termination of the bevel 2| therein.

In order to remove the plug it is merely necessary to force water downthrough a hydraulic pressure apparatus, such as a pump, from above withsufilcient force to dislodge the plug, whereupon it falls freely downinto the well and out of the way, or, in lieu of water pressure, aweight may be dropped down into the tubing and by the blow delivered tothe plugs cause its dislodgment from the position as shown in Fig. 1Under either of these modes of dislodgment of the plug it will be seenthat the downward pressure must be suflicient' to crowd the expansionring inwardly into its groove H, thereby permitting free downwardmovement of the plug.

In the modification illustrated in Fig. 2 I employ a disk 22 providedwith a groove in its periphery, 23, in which is seated a split expansionring I which may be identical in construction with the ring Iillustrated in Fig. 1. In this modification, the upper outer face of thedisk 22 seats against the ground seat 24 in the tubing section In, toprovide a leak-tight joint against the upward passage of oil. In thisrespect the modification follows the construction of the disk section tof the plug shown in Fig. 1. The tubing section 2a is shown as connectedwith an upper section In by a threaded collar la, and the lower portionof the section in is threaded for engagement therewith by a couplingcollar, the lower inner portion of which is in threaded engagement witha lower tubing section 30. The

. expansion ring it is received in the groove 23 in the outer peripheralface of the ring 22,.and when the latter is seated against the seat 24in the tubing the expansion ring is in frictional engagement with theseat 28 in the inner wall of the tubing, below the ground seat 24, asshown in Fig.2. Dislodgment of the disk in this case is. effected byeither of the means described with reference to the construction shownin Fig. 1; that is, either of downward hydraulic pressure,

. or due to the force of a blow delivered by impact the plug when thelatter is dislodged, due to the curved bullet-shaped extension I! whicheffectively prevents any liability of the plug lodging in the tubingbelow the seat of the plug, and becoming fixed" in a c'rosswire positiontherein.

Iclaim:- 1. Abottomtubingplusforoilwellscomprising a disk having itsupper face ground to form a tight joint with the seat in a tubingsection, said device provided with a peripheral groove, and a resilientexpansion ring seated in the groove and arranged to frictionally engagea groove within the tubing section.

2. A bottom tubing plug for oil wellscomprising in combination, asection having a convexly curved outer terminal face, a groove formedpartly in said sectioman expansion ring fitting said groove, a diskcombined with said section and arranged to overlap the groove at itslower edge, and having its upper edge ground to form a surface to seatagainst a ground seat formed interiorly of the well tubing.

3. A bottom tubing plug for oil wells comprising a section having anouter convexly curved terminal portion having its upper portion reducedin diameter to form a recess, an expansible elastic ring in said recess,an upper disk portion constructed to overlap said recess forming agroove for said ring, and means for clamping the two portions of theplug together.

4. A bottom tubing plug for oil wells having in combination, a lowerbullet-shaped portion havdropped through the tubing, an upper reducedportion to form a recess, an expansion ring in said recess, a diskoverlapping the recess and provided with a valve seat at its upperperipheral edge to engage the seat in the tubing, and clamping means forsecuring the several parts of the plug together.

6. In a device of the character described, the combination with an oilwell tubing section provided interiorly with a valve seat facingdownwardly, a recess below said seat for receiving an expansion ring, aninclined portion formed below the said recess, of a plug comprising adisk mem ber constructed to engage the tubing seat, an extension memberbelow the disk provided with a recess, a curved lower end extending asubstantial distance below the recess, an expansion ring in said recess,and means for clamping the several parts 01 the plug together.

; K. EDWARDS.

comprising a lower section having a reduced terminal to provideclearance for the plug when

